Electrical vernier type telemetric



Sept. 7, 1948. c. A. DE GIERS ET AL 2,443,783

ELECTRICAL VERMIER TYPE TELEMETRIC INDICATING SYSTEM Filed Sept. 29,1944 5 Sheets-Sheet 1 l l lmlllgny; I

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ELECTRICAL VERMIER TYPE TELEMETRIC INDICATING SYSTEM Filed Sept. 29,1944 s Sheets-Sheet 2 aka/ms BY M 21), c.

AZ TOEZYEY Sept. 7, 1948. c. A. DE GIERS ET AL 2,448,783

ELECTRICAL VERMIER TYPE TELEMETRIC INDICATING SYSTEM Filed Sept. 29,1944 3 Sheets-Sheet 5 INVENTORS C2 flea c5 594-- 620?; (00/5 M CAMP/9AATTORNEY Patented Sept. 7, 1948 UNITED STATES PATENT OFFICE ELECTRICALVERNIER TYPE TELEMETRIC INDICATING SYSTEM Application September 29,1944, Serial No. 556,330

3 Claims. (Cl. 177-351) This invention relates generally to improvementsin indicating devices and has particular reference to improvements inelectrically controlled indicating devices.

One object of the invention is to provide means to increase the accuracyof the indications of the device.

Another object is to provide means for ampliiying or enlarging the scalethe device on which the indications appear.

Another object of the invention is to provide a scale for coarseindications and a second scale for line indications, the entire range ofthe fine scale being arranged to correspond to a fraction of the rangeof the coarse scale.

still another object of the invention is to provide means by which theamplification and enlargement of the indications are obtained withoutany, or at least without any substantial, increase of the size of theindicating device.

Indicating devices according to the invention can be advantageously usedfor the measurement of liquid levels, pressures, temperatures, etc. Theycan be employed in many fields of application. However, it should benoted that they are particularly useful where the available space islimited. For example the panel space in present aircraft is very limiteddue to the multi plicity of instruments required for the operation ofsuch aircraft. Hence, size and scale length of each indicator arenecessarily limited thus reducing the readability and accuracy of thesystem. The above enumerated features of the invention eliminate thesedifficulties by providing the equivalent of a long indicator scalewithout increasing the size of the indicator, particularly of its dial.

Other and further features and advantages of the invention will appearhereinafter and in the appended claims forming part of thespecification.

In the accompanying drawings several embodiments of the invention areshown by way of illustration and not by way of limitation.

Figure 1 is a plan view of an indicator according to the invention,

Figure 2 is a fractional perspective view of a transmitter suitable forthe operation of the indicator shown in Figure 1,

Figure 3 is an electric circuit diagram schematically illustrating oneembodiment of the in ventlon,

Figure 4 is a schematic view of a tank having a non-uniform crosssection,

Figure 5 is a schematic circuit diagram of a modified form of atransmitter which may be used in conjunction with the tank ofnon-uniform cross section shown in Figure 4,

Figure 6 is a plan view oi an indicator suitable for use with thepresent invention and having a 360 scale, and

Figure 7 is a schematic circuit diagram of another modiflcatlon of theinvention, suitable for operation with a 360 indicator as shown inFigure 6.

The circuit diagram shown in Figure 3 comprises an indicator ll alsoshown in Figure 1 which includes ratiometers 81 and 38. The ratiometer37 comprises deflecting coils 31a and 31b. One end of coil 31a isgrounded, the other end is connected to one end of coil 31b. The coilscontrol the position of a magnetized rotor fle which carries a pointerit playing over a scale It. This scale is calibrated in units to bemeasured, for example, in gallons when gasoline in a tank is to beindicated. The illustrated scale II has a range of gallons subdividedinto units of 10 gallons. The ratiometer 31 further comprises a scalecontrol coil 31c which is grounded at one end and connected at the otherend to one end of a resistor 31d. Coil 31c determines the total lengthof the scale l5 depending on the current allowed through it by resistor31d. This resistor and one end of ratiometer coil 31b are connectedthrough a series resistor 49 to one terminal of a source of current 41,the other end of which is grounded. A conventional zero return magnet(not shown) may be provided to bring pointer ll below "0 to indicatewhen the ratiometer is not in use. The second ratiometer 38 is similarto ratiometer 31. It comprises defleeting coils 30a, "D, a magnetizedrotor 38c, supporting a pointer l8 playing over a scale ii, a scalecontrol coil "c, a resistor 38d and a series resistor 48. Means arepreferably provided to prevent pointer I! to drop below "0 on scale I1.These means may consist of a proper adjustment of a conventional zeroreturn magnet or a pointer stop 38!. Scale IT is subdivided into 10units. The entire range of scale I! is arranged to correspond to amovement of pointer it from "0" to 10" or 10" to 20" and so on. It is ofcourse also possible to calibrate scale I! for any other fraction of therange of scale it.

Ratiometers of the type previously described are fully disclosed andillustrated in U. 8. Patent 2,339,021 granted January 11, 1944, toFrederick J. Lingel. However, it should be noted that other suitabletypes of ratiometer may likewise be used. Furthermore milliammeter typesof indicators may also be employed if suitable provisions can be madefor a constant supply of current.

The ratiometers are controlled by a transmitter l3 shown in Figures 2and 3. This transmitter comprises two strips 2| and 22 preferably madeof insulating material such as known under the trade name Bakelite andmounted on a suitable base 20. Strip 2| supports a single resistancewinding 2|a extending substantially throughout the entire length ofstrip 2|. Strip 22 supports a multiplicity of resistance windings suchas 22a, 22b, 22c, 22d and 22e all having normally the same resistance.The left hand ends of all windings 22a, 22b, etc., are connected to acommon lead 22' connected to a terminal 43 which in turn is connectedthrough lead 42 to a point 38g. The right hand ends of windings 22a,22b, etc., are connected through a common lead 22" to a terminal 44which is grounded. Hence all the resistance windings on strip 22 areconnected in parallel. The number of windings on strip 22 depends on theindividual application. It may vary from two to as many as are possiblewithin practical limits. Cooperating with the resistance winding onstrip 2| and resistance windings on strip 22 are wiper arms 23 and 26respectively.

These wiper arms are electrically insulated by system applied to a fork32, for example, the linkage system may support a float floating upon aliquid such as gasoline the level of which then will determine theangular position of fork 32 and hence of wipers 23 and 26. Figure 3indicates schematically a float 45 which is operatively connected withsupport 3| and a retraction Spring 43 and will consequently determinethe angular position of this support. Wiper 23 has an extension 23'engaging a bracket 24 connected to a terminal 25 which in turn isconnected to one end of coil 31a through a lead 39. Wiper 26 has anextension 26' engaging a bracket 21 extended to a terminal 28 which isconnected to one end of coil 38a through a lead 4|. Contact shoes 33 and34 respectively operated through eccentric adjustment screws 35 and 36respectively serve to make contact with the ends of winding 2|a and alsoas scale adjustments for scale l5. Adjust ment means of this type arefully described in U. S. Patent 2,195,813, patented April 2, 1940, toClarence A. de Giers and are not part of this invention. Similaradjustment means may be provided if desired for the resistance windingson strip 22. Contact shoe 33 is connected by a lead to a point 31g andcontact shoe 33 is grounded. Transmitter winding 2|a operates ratiometer37 of the indicator l4 and transmitter windings 22a, 22b, etc., controlratiometer 38.

A short circuiting contact 38h connected to common lead 22' may beprovided to return pointer l8 into the zero position after havingcovered its entire range on scale ll.

The system illustrated in Figure 3 is a grounded system. However,ungrounded systems may be used also. Then a connection .must be providedbetween one terminal of the source of supply 41 and the transmitter.

The operation of the invention will now be described in detail inconnection with the measurement of liquid levels. Assuming that floatshown in Fig. 3 is at its bottom position, then 4 wipers 23 and 26will-be on axis e and pointer It will indicate 0 on scale l5, whilepointer I8 will be on "0" of scale As float 45 begins to rise, due to anincrease of the liquid level to be measured, wipers 23 and 28 will moveover the respective windings simultaneously toward axis f. Theindividual windings 22a, 22b, etc., are adjusted so that pointer I8 willcover its entire range when pointer l6 moves from 0 to.10, from 10" to20, etc. Consequently when axis 1! is reached, pointer It will indicate10" on scale l5 while pointer l8 will have traveled the full length ofscale H to calibration mark 10. Thus for this displacement, the distancebetween 0 and 10" on scale l5, which may normally be 18, has beenamplified to a distance from 0 to "10 on scale IT, or approximately 90.When the wipers reach axis f, wiper 28 will engage the end of winding22a and the beginning of winding 221), or in effect, points 13 and 44.This de-energizes element 38 of indicator l4 causing the pointer |8 todrop back to 0" on scale ll. As soon as wiper 2B loses contact with theend of Winding 22a, and is making contact with the beginning of winding22b, only. element 38 will be at the same electrical potential as whenthe wiper was at the beginning of winding 22a. The cycle, therefore,will be repeated. When the wipers 23 and 26 travel from axis 1 to g,pointer l6 will move from 10" to 20 on scale l5, and pointer l3 willagain travel the full length of scale ll from 0 to 10. Upon reachingaxis 9, wiper 26 will engage the end of winding 22b and the beginning ofwinding 220. Points 43 and 44 will again be shorted, and pointer I8 willdrop back to "0 ready to start a third cycle. The same action isrepeated at axis h; l and y, and at as many other points for which thesystem is designed. When the wipers reach the end of their stroke, axis7', pointer l6 will to zero.

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It will now be realized that readings taken on indicator l4 will'beindicated on the combination of two scales. Thus, for example, scale |5may indicate tens of a unit, while scale l'l indicates single units. Theefiective length of the scale is thereby increased as many times asthere are windings on strip 22 of the transmitter. If, in the exampleshown, the liquid level was measured with an indicator not provided withthe elements of this invention, that is if an indicator such asindicator ll of Fig. 1, would be equipped only with a scale IS thereadings taken on scale I5 of this indicator by pointer l6 would belimited to Hence the particular reading illustrated could only beestimated to be approximately 7 or 8. However, with the indicatoraccording to the invention shown on Figs. 1, 2 and 3, the total lengthof the scale is in eilect 5 x 90 or 450. The reading which was roughlyestimated at '7 or 8" on scale I 5, can now be more definitelydetermined to be 7 on the unit scale I! of indicator ll. 1

In the above specification, it has been assumed that the changes of thequantity to be measured are uniform. However, in many cases for examplein the measurement of fluid levels the indicator is complicated,inasmuch as volume is intended to be measured and the volume due topeculiarities in the shape of the retaining vessel, is often notproportional to the height of the fluid. Fig. 4 illustrates a tank ofnonuniform cross section. For the purpose or illustration, the tank hasbeen shown to be of 40 gallons capacity and with sides sloping towardthe bottom. It will be apparent from the drawing that the height of thefirst 10 gallons will be 2.34 times the height h. of the last 10gallons. In order to make the system responsive to volume, transmitter50 is modified, as shown in Fig. 5. The circuit shown in Fig. 5 isbasically the same as that shown in Fig. 3, except for diflerenceshereinafter noted. The windings 5ia, Sib, lie and 5id are all normallyof the same resistance and, as in the previous case, are parallelconnected to points 54 and 85. Each winding, however, is wound so thatits length is in proportion to the corresponding height in the tank.Thus winding 5ia, Fig. 5 represents the first 10 gallons in tank 58,Fig. 4, or the height from level 1:2 to L2. Likewise, winding 5idrepresents the last 10 gallons in tank 55, or the height from level 112to 02. Since the height of the first 10 gallons is, in this case, 2.34times the height of the last 10 gallons, the length of winding 5ia, willalso be 2.34 times the length of winding 5id, even though they are ofthe same resistance value. In order to insure maximum accuracy in thesystem, each winding Ma, 5), 5 lo and 5id can further be wound tocompensate for the non-uniformity of the cross section of the tankwithin the range of said winding. Windings 5ia, 5ib, etc., can be taperwound to conform to the slope of the side of the tank so that for everygallon in the tank the wiper will travel over the same resistanceincrement. Under this condition "single unit scale 59 can be made anessentially even scale for practically any shape of tank, and is equallyapplicable at any level in the tank. Winding Zia operating element 3'!has been shown of uniform resistance. This will result in a non-uniformcalibration as shown on scale 51. This scale may be made more uniform bymaking winding '2ia tapered as has been done for the windings 5ia 5ib,5ic and 5id. This, however, is not necessary since the intermediatereadings between all the graduations of scale 51 can be taken on scale59 and hence are made more uniform in this scale.

In operation, when the float 45 corresponds to level M, of the tankshown on Fig. 4, wipers 25 and 29 will be at axis kl and pointer i5 willindicate on scale 51, while pointer 3 will indicate O on scale 59. Asthe fioat rises to level L2, Fig. 4, the wipers will move simultaneouslyto axis Li. Pointer IE will now indicate l0 and pointer [8 will havetravelled the full length of scale 59 to point 10. At this point, wiper25 will engage the end of resistance strip Bid and the beginning ofresistance strip ib, causing the pointer i8 to return to zero asexplained in conjunction with Fig. 3. As the fluid rises from level L2to m2, Fig. 4, the wipers will move from axis Li to mi Fig. 5, causingpointer i5 to move from 10 to "20," and pointer i8 will again movethrough the range of scale 59. It should be noticed here that eventhough wiper 26 has covered proportionally less winding in moving fromLi to mi than it did when moving from kl to Li; in both cases the entirescale 59 was covered and that for each cycle a 10 gallon increment wascovered. The same conditions are repeated for the cycles correspondingto the wiper movement from mi to ni and ni to oi.

The principles applied to an indicator of the 90 or 120 type can also beapplied to indicators having a full 360 of rotation. Fig. 6 shows anindicator 69 having two scales 10 and II and calibrated for 50 gallons.Scale I5 is the fine scale and is extended over a full 360. This scaleis divided into ten parts, not necessarily of equal increment. Scale iiis the coarse scale, not necessarily a 360 scale. It is subdivided andcalibrated according to the application at hand. In reading theindicator, the indication of pointer 73 is taken on scale ii for the"tens (or other unit), and the "units are indicated by pointer 12 onfine scale 10. The scale of the indicator is thus in effect greatlyamplified and in this particular application pointer 12 will make fivecomplete revolutions while pointer 13 travels from "0" to "50 gallons aswill be explained more fully hereinafter. In the illustration shown, theindicator reads 17.

Fig. 7 shows a circuit diagram suitable for the operation of indicator59, Fig. 6. The transmitter comprises two resistor strips M and i5.Winding i5 is tapped at points 9i and 82 and by scale ad- Justmentcontacts and 85 Joined together by lead 54 which is connected to anelement 15 of indicator 59 through connection leads 85, 8S and 91.Element 15 is comprised of three flux producing coils Ila, 15b and 180cooperating with a permanently magnetized rotor 16d which carriespointer 79. Three series resistors 18a, 78b, 780 complete the circuit byconnecting coils 76a, 76b, 19c, to the source of current 41. Thiscircuit in itself is not a part of the present invention. Windingelement 14 may be one continuous winding, tapped to suit requirements.In the case shown in Fig. 7 resistance winding 14 is divided into fivesections 14a, 14b, 14c, 14d and Me. These taps are all connected by acommon lead terminal 89. form three sub-sections, such as by taps 89aand 90a of section Ha, taps 89b and 90b of section 14b, etc. Taps 89a,89b, 89c, 89d and 89e are connected by a common lead to a terminal 89,while taps 90a, 90b, 90c, 90d and We are connected by a common lead to aterminal 90. The individual sections thus formed may be taper wound.Terminals 88, 89 and 90 are connected to element 11 01 indicator 59through connection leads 9|, 92 and 93 respectively. Element 11 issimilar to element 15. and need not be described further. Wipers 95 and95 are mechanically connected. Since both are grounded, they may also beelectrically connected.

In operation, when the moving element of the transmitter is in aposition represented by axis a, Fig. '7, wiper 95 will be directly overtap 88a causing the pointer 12 to read 0 on scale 10. Simultaneouslywiper 96 will be slightly past tap 80 on winding 15 causin the pointer13 to read "0 on scale 1i. As the wipers move from axis a to b, thepointer 13 will move from "0 t 10. Wiper 95 will have travelled from tap88a to tap 89b, which is at the same potential. Hence the pointer 1'2will have travelled from "0 around 360, back to "0 (or 10). As thewipers continue to travel from axis b to axis 0, pointer 13 will travelfrom "10 to "20 on scale 1i, and pointer 12 will have made anotherrevolution around scale iii. The process will be repeated until themoving element of the transmitter has completed its travel across thewindings.

When applied to tanks for liquids, the same compensation for anirregular shape of said tanks that has been applied in the arrangementshown on Fig. 5 can be applied to this system.

It is understood that all numerical values shown are merely for thepurpose of illustration and that other values and/or proportions may beused Each section is again tapped to v s me . t to suit a particularapplication. Also. the arrangements of the pointers need not beconcentric as shown in Fig. 1. The physical arrangement of the twoscales may be varied in any desired manner without departing from thescope of the invention.

While the invention has been described in detail with respect to certainpreferred examples and embodiments, it will be understood by thoseskilled in the art after understanding the invention that variouschanges and modifications may be made without departing from the spiritand scope of the invention and it is intended therefore, in the appendedclaims, to cover all such changes and modifications.

We claim:

1. Telemetric device comprising an electrically controlledindicatingmeans including a permanently magnetized rotor and a plurality ofdeflecting coils eflective to control the position of said rotor forcoarse indications, said indicating means being calibrated to indicate arange including a plurality of units to be measured, a sim-. I

ilar electrically controlled indicating means including a. permanentlymagnetized rotor and a plurality of deflecting coils effective tocontrol the position of said rotor for fine indications, said fineindicating means being calibrated to indicate one unit of the totalrange of the coarse indicating means on an enlarged scale; controllingmeans including a resistor electrically connected in a circuit with thedeflecting coils of said coarse indicating means and a source ofcurrent, a plurality of resistance elements connected in parallel in acircuit with the deflecting coils of said fine indicating means and saidsource of current, corresponding terminals of each of said resistanceelements being at the same potential, said resistance elements beingequal in number with the number of units measured by the coarseindicating means, a contact slidably engaging the resister for changingthe eflective resistance value thereof, asecond contact constructed toslidably engage successive resistance elements for changing theeffective resistance value of the engaged resistance element, saidresistance elements all having the same total resistance but being sowound, disposed and arranged as to extend over r of one of saidresistance elements thereby causihg the fine indicating means to movethrough its total range when and while the first slider contact is movedover a single section of said resistor causing the coarse indicatingmeans to move through one of the units thereof.

2. A-telemetric device in accordance with claim 1,,ggh'erein saidresistor of the transmitter for coarse indicating means is a singlecontinuous 19 re stor wound on an insulating element and having theturns thereof engaged by the first-named slidable contact, and whereinthis resistor and two series connected deflecting coils of said coarseindicating means are both connected in parallel across said source ofcurrent, said resistor actins as a potentiometer resistance; and whereineach of said resistance elements is a resistance coil wound on aninsulating support and having the turns thereof directly engaged by saidsecond contact, all said resistance elements being electricallyconnected in parallel with one anothbr and each being connected as apotentiometer resistance across said source of current, two seriesconnected deflecting coils of said fine indicating means being alsoelectrically connected in parallel with said resistance elements andacross said source of current; and means electrically connecting thefirst named slidable contact to the connection between the twodeflecting coils of said coarse indicator, and other means electricallyconnecting said second contact with the connection between the twodeflecting coils of said fine indicating means.

3. A telemetric device in accordance with claim 1, wherein said resistoris a single continuous resistance coil wound on an insulating supportand having the turns thereof engaged directly by the first-namedslidable contact, conductors electrically connecting both ends of saidresistor to one another and to said coarse indicatin means, and twoother conductors respectively connecting the one-third and two-thirdspoints along said resistor with the deflecting coils of said coarse'indicating means, said coarse indicating means having three deflectingcoils effective by the relat-ive current flow therethrough to move anindicator through a substantially 360 path; and wherein said resistanceelements are formed as parts of a single continuous resistance coil.wound on an insulating support, and the turns of which are engaged bysaid second contact, wherein said fine indicating means is a 360ratiometer-type instrument similar to said coarse indicatinl means andincluding three deflecting coils, and electric conductors connectingeach of said resistance elements with said deflecting coils of the fineindicating means in the same manner as said resistor of the coarseindicating means is connected to its respective indicating means, eachsection of the resistance coil making up said resistance elements beingconnected substantially in parallel with every other section.

CLARENCE A. Dr: GIERS. LOUIS M. CAMPANI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,691,360 Reagan Nov. 13, 19282,132,213 Locke Oct. 4, 1938 2,148,075 Kiner Feb, 21, 1939 2,198,055Liner Apr. 23, 1940 2,216,069 Doyle Sept. 24, 1940 2,289,202 McCoy July'7, 1942 2,388,559 Macintyre Nov, 6, 1945 2,391,058 Lingel Dec. 18, 19452,396,244 Borsum Mar, 12, 1946 FOREIGN PATENTS Number Country Date102,104 Great Britain Nov, 16, 1916 104,777 Great Britain Mar. 22, 1917

